1. Field of the Invention
This invention is directed to novel compositions comprising undecamantanes. This invention is also directed to novel processes for the separation and isolation of undecamantane components into recoverable fractions from a feedstock containing at least one or more undecamantane components.
The following publications and patents are cited in this application as superscript numbers:
1 Lin, et al., Natural Occurrence of Tetramantane (C22H28), Pentamantane (C26H32) and Hexamantane (C30H36) in a Deep Petroleum Reservoir, Fuel, 74(10):1512-1521 (1995).
2 Alexander, et al., Purification of Hydrocarbonaceous Fractions, U.S. Pat. No. 4,952,748, issued Aug. 28, 1990.
3 McKervey, Synthetic Approaches to Large Diamondoid Hydrocarbons, Tetrahedron, 36:971-992 (1980).
4 Wu, et al., High Viscosity Index Lubricant Fluid, U.S. Pat. No. 5,306,851, issued Apr. 26, 1994.
5 Chung et al., Recent Development in High-Energy Density Liquid Fuels, Energy and Fuels, 13, 641-649 (1999).
6 Sandia National Laboratories (2000), World""s First Diamond Micromachines Created at Sandia, Press Release, (Feb. 22, 2000) www.Sandia.gov.
7 Balaban et al., Systematic Classification and Nomenclature of Diamondoid Hydrocarbons-I, Tetrahedron. 34, 3599-3606 (1978).
8 Chen, et al., Isolation of High Purity Diamondoid Fractions and Components, U.S. Pat. No. 5,414,189 issued May 9, 1995.
All of the above publications and patents are herein incorporated by reference in their entirety to the same extent as if each individual publication or patent was specifically and individually indicated to be incorporated by reference in its entirety.
2. State of the Art
Undecamantanes are bridged-ring cycloalkanes. They are the face-fused undecamers of adamantane (tricyclo[3.3.1.13,7]decane) or C10H16 The compounds have a xe2x80x9cdiamondoidxe2x80x9d topology, which means their carbon atom arrangement is superimposable on a fragment of the diamond lattice (FIG. 1). Undecamantanes possess eleven of the xe2x80x9cdiamond crystal unitsxe2x80x9d and therefore, it is postulated that there are hundreds of possible undecamantane structures which exist in different molecular weight core structures. Among them, there are undecamantanes having the molecular formula C39H40 (molecular weight 508) of which two are structurally compact in relation to the other undecamantanes. Undecamantanes also have the molecular formulas: C50H56 (molecular weight 656), C49H54 (molecular weight 642), C48H52 (molecular weight 628), C46H50 (molecular weight 602), C46H48 (molecular weight 588), C42H44 (molecular weight 548), and C41H42 (molecular weight 534).
Little or no published work is available for undecamantanes and higher molecular weight diamondoids. Undecamantane compounds have not been artificially synthesized or isolated and these higher diamondoids along with hexamantane, heptamantane, octamantane, nonamantane and decamantane compounds have been recently thought only to have a theoretical existence.7 Academic chemists have primarily focused research on the interplay between physical and chemical properties in lower diamondoids such as adamantane, diamantane and triamantane. Adamantane and diamantane, for instance, have been studied to elucidate structure-activity relationships in carbocations and radicals.3 Process engineers have directed efforts toward removing lower diamondoids from hydrocarbon gas streams.2 These compounds cause problems during the production of natural gas by solidifying in pipes and other pieces of equipment.
The literature contains little information regarding practical applications of higher diamondoids and even less, if any, information regarding undecamantanes. This fact is probably due to extreme difficulties encountered in their isolation and due to failed synthesis attempts. Lin and Wilk, for example, discuss the possible presence of pentamantanes in a gas condensate and further postulate that hexamantane may also be present.1 The researchers postulate the existence of these compounds contained within petroleum solely based on a mass spectrometric selected ion monitoring (SIM) and mass spectral fragmentation patterns. They did not, however, report the isolation of a single pentamantane or hexamantane nor mention heptamantane, octamantane, nonamantane, decamantane or undecamantane. Nor were they able to separate non-ionized components during their spectral analysis. McKervey et al. discuss an extremely low-yielding synthesis of anti-tetramantane.3 The procedure involves complex starting materials and employs drastic reaction conditions (e.g., gas phase on platinum at 360xc2x0 C.). Although one isomer of tetramantane, i.e. anti-, has been synthesized through a double homologation route, these syntheses are quite complex reactions with large organic molecules in the gas phase and have not led to the successful synthesis of other tetramantanes. Similar attempts using preferred ring starting materials in accordance with the homologation route, have likewise failed in the synthesis of pentamantanes. Likewise, attempts using carbocation rearrangement routes employing Lewis acid catalysts, useful in synthesizing triamantane and lower diamondoids have been unsuccessful in synthesizing other tetramantanes or pentamantanes. No attempt to synthesize or isolate undecamantanes has been reported.
Among other properties, diamondoids have by far the most thermodynamically stable structures of all possible hydrocarbons that possess their molecular formulas due to the fact that diamondoids have the same internal xe2x80x9ccrystalline latticexe2x80x9d structure as diamonds. It is well established that diamonds exhibit extremely high tensile strength, extremely low chemical reactivity, electrical resistivity greater than aluminum trioxide (Al2O3), excellent thermal conductivity, and superb optical properties.
In addition, based on theoretical considerations, the undecamantanes have sizes in the nanometer range and, in view of the properties noted above, the inventors contemplate that such compounds would have utility in micro- and molecular-electronics and nanotechnology applications. In particular, the rigidity, strength, stability, variety of structural forms and multiple attachment sites shown by these molecules makes possible accurate construction of robust, durable, precision devices with nanometer dimensions. The various undecamantanes are three-dimensional nanometer sized units showing different diamond lattice arrangements. This translates into a variety of rigid shapes and sizes for the undecamantane components. For example, [1212121212] undecamantane is rod shaped and [123(1,2)42143] undecamantane is somewhat pyramidal in structure. A variety of other shapes exist among the undecamantanes which may serve in applications which depend upon specific geometries. It has been estimated that MicroElectroMechanical Systems (MEMs) constructed out of diamond should last 10,000 times longer then current polysilicon MEMs, and diamond is chemically benign and would not promote allergic reactions in biomedical applications.6 Again, the inventors contemplate that the various undecamantanes would have similar attractive properties. Furthermore, many of the undecamantanes would possess chirality, offering opportunities for making nanotechnology objects of great structural specificity and ones which have useful optical properties. Applications of these undecamantanes include molecular electronics, photonics devices and production of nanomechanical devices, and other materials.
Notwithstanding these advantages of undecamantanes, the art, as noted above, fails to provide for compositions comprising undecamantanes or for processes that would lead to these compositions. In view of the above, there is an ongoing need in the art to provide for compositions comprising one or more undecamantanes.
This invention is directed to novel compositions comprising one or more undecamantane components.
Accordingly, in one of its composition aspects, this invention is directed to a composition comprising one or more undecamantane components wherein said composition comprises at least about 25 weight percent undecamantane components based on the total weight of the diamondoids in the composition.
In another of its composition aspects, the compositions preferably comprise one or more undecamantane components wherein the undecamantane components make up from about 50 to 100 weight percent, preferably about 70 to 100 weight percent, more preferably about 90 to 100 weight percent and even more preferably about 95 to 100 weight percent of the total weight of the diamondoids in the compositions.
In another of its composition aspects, the compositions comprise at least about 10 weight percent and preferably at least about 20 weight percent of undecamantanes based on the total weight of the composition. Other compositions of this invention contain from 50 to 100 weight percent, 70 to 100 weight percent, 95 to 100 weight percent and 99 to 100 weight percent of undecamantanes based on the total weight of the composition.
In another of its composition aspects, the compositions preferably comprise from about 70 to 100 weight percent, more preferably from about 90 to 100 weight percent, even more preferably from about 95 to 100 weight percent and most preferably from about 99 to 100 weight percent of a single undecamantane component, including isolated optical isomers thereof, based on the total weight of the composition.
Compositions are sufficiently enriched in undecamantane components the undecamantanes can form crystal structures. Accordingly, another aspect of this invention is directed to a composition comprising an undecamantane crystal. Since such undecamantane can co-crystallize, another aspect of this invention is directed to the co-crystals comprising crystals of at least two undecamantane components or a undecamantane component and another higher diamondoid component.
This invention is also directed to novel processes for the separation and isolation of undecamantane components into recoverable fractions from a feedstock containing one or more undecamantane components and nonundecamantane materials. These processes for recovering a composition enriched in undecamantane components entail removing at least a portion of the nonundecamantane materials which have a boiling point below the lowest boiling undecamantane component and utilizing a subsequent separation technique to recover undecamantane components from the resulting residue. Accordingly, this aspect is directed to processes which comprise:
a) selecting a feedstock comprising recoverable amounts of undecamantane components and nonundecamantane materials;
b) removing from the feedstock a sufficient amount of nonundecamantane materials that have boiling points below the boiling point of the lowest boiling point undecamantane component in the feedstock under conditions to form a treated feedstock enriched in undecamantane components which can be recovered;
c) recovering undecamantane components by separating said treated feedstock formed in b) above with one or more additional separation techniques selected from the group consisting of chromatographic techniques, thermal diffusion techniques, zone refining, progressive recrystallization and size separation techniques.
In a preferred embodiment, after the step recited in b) the undecamantane components in the treated feedstock can be thermally treated to pyrolyze at least a sufficient amount of nondiamondoid components therefrom under conditions to provide a thermally treated feedstock retaining recoverable amounts of undecamantane. Such a pyrolization step prior to step c) is useful for thermally degrading at least a portion of any materials remaining in the treated feedstock having a thermal stability lower than the undecamantane components in common hydrocarbonaceous feedstocks. This pyrolysis step can be carried out in step b) if desired.